Oct 07, 2019· Hardgrove grindability is a measure of the relative ease with which a coal sample can be pulverized or ground to smaller sizes. All mined coals need to be ground to very small sizes (often powder size) before being utilized.
In coal utilization: Grindability for assessing grindability is the Hardgrove test, which consists of grinding a specially prepared coal sample in a oratory mill of standard design. The percent by weight of the coal that passes through a 200-mesh sieve (a screen with openings of 74 micrometres, or 0.003 inch) is used to calculate Read More
Hardgrove Grindability Index (short HGI) is a measure for the grindability of coal. Grindability is an index, therefore it has no unit. The smaller the HGI, the harder is coal texture and less grindable is the coal. Grindability is an important factor for the design a coal mill. As grindability depends on many unknown factors, HGI is determined
In coal utilization: Grindability is used to calculate the Hardgrove grindability index (HGI). The index is used as a guideline for sizing the grinding equipment in a coal-preparation plant.
Oct 07, 2019· Float-sink (washability) : determines the relative amount of coal that can be separated from attached rock and minerals ; Hardgrove grindability: determines how easily coal can be crushed ; Major and minor elements by X-ray fluorescence: determines the elemental composition of coal and coal
A general prediction model for the Hardgrove grindability index was constructed from 735 coal samples using the proximate analysis, heating value, and sulfur content. The coals used to develop the general model ranged in volatile matter from 12.8 to 49.2 percent, dry basis, and had grindability indexes ranging from 35 to 121.
An improved predictor of coal pulverization behavior and coal feed rate is under development at the CAER based upon the interaction between Hardgrove Grindability Index (HGI) and coal petrology. With educated attention, this interaction may be a useful tool to enhance coal feed rates if cautiously extended to the mining environment where blends
Studies of the relationship between petrography and grindability for Kentucky coals using artificial neural net. International Journal of Coal Geology 73(2), 130 138. Google Scholar Crossref ISI
International Journal of Coal Geology, 54: 253-260. Ural, S., Akyildiz, M. 2004. Studies of the relationship The most commonly used measurement of coal grindability is the Hardgrove
Jan 21, 2008· Coal grindability is a complex property related to coal hardness, strength, tenacity, and fracture. All these properties are influenced by coal rank, petrography, the type and distribution of minerals, megascopic coal lithology, and microscopic maceral associations (Hower, 1998).
Indonesia has the largest coal reserves in the south-east Asian region. According to estimates from the World Energy Confer- ence, it has reserves of 18 billion mt lignite, 4.4 billion mt sub-bituminous coal and 774 million mt bituminous coal (Wyllie,1988). In recent years, substitution of coal for oil in power plants has been the goal
Hardgrove Grindability, Coal Analysis, Kentucky Geological Hardgrove Grindability Index Hgi Linkedin Slideshare. May 01 GRINDABILITY OF COALThe measure of the coal resistanceto crushing is said to be the grindability of a coalGenerally lignite and anthracites are more resistant togrinding than bituminous coals Two major factors themoisture
Imanishi (1985) carried out grindability tests of various types of ore and coal and a new classification of iron ores was proposed on the basis of the ore forming temperature of deposits. The inds of magnetite and hematite minerals ranged between 12.5 approx 24.1 KWh/ton and 6.5 approx 23.8 KWh/ton, respectively, and, in both cases
Sep 01, 2014· Coal grindability characteristics reflect the coal hardness, tenacity and fracture that are influenced by coal lithotypes, maceral composition, rank and the distribution and the types of minerals (Bagherieh et al., 2008, Chehreh Chelgani et al., 2008, Ganguli and Bandopadhyay, 2008, Hower, 1998, Hower and Calder, 1997, Hower and Wild, 1988
For example, hardness and grindability of coal determine the maintenance cost for coal mining, handling and grinding equipments. The specific gravity of coal and its associated minerals determines coal preparation or washing techniques requirements. Following are some important physical properties of coal